This application requests support to continue the program of psychobiological research in the Deaprtment of Psychiatry, Emory University School of Medicine. The School of Medicine together with the Georgia Mental Health Institute wish to support a comprehensive research program that is basicto problems offbrain function, behavior and mental health. The aim isto investigate the physiological and, in particular, the neuroendocrine basis of patterns of primate behavior. Emphasis is placed o patterns of instinctive and of emotional behavior, on the affectional and sexual responses, an also on the agonistic and aggressive responses. Central to this program is the accurate quantification ofprimate behavior using ethological tecniques both in thedyadic situation and in the social group. We are concerned with understanding the physiological mechanisms that determine an animal's motivational state in terms of the underlying brain mechnaisms involved. This necessitates utilization of brain implantation techniques with steroid hormones, operant conditioning techniques, and the radioimmunoassay of plasma steroids; emphasis is placed on a multidisciplinary approach. Detailed attention will be given to the mechanisms by which information concerning an animal's motivational state is communicated to conspecifics, andthis necessitates an understanding of the inormational content of behavioral displas, and also of te chemical communication signaling systems involved.